What Causes Low Estrogen? 5 Common Reasons

Wondering what causes low estrogen—and why it can leave you moody, foggy, or wide awake at 3 a.m.? You’re not alone. As someone smack in the middle of perimenopause, I’ve had a front-row seat to my hormones’ rollercoaster—shorter cycles one month, 38-day marathons the next, brain fog that steals words mid-sentence, and mood swings that make me snappier than a snapping turtle. With my estradiol levels on the decline, it’s clear just how much estrogen does behind the scenes.

Estrogen isn’t just about periods or pregnancy; it keeps bones strong, cholesterol in check, and moods steady, among other things. So when it dips? You feel it. For people in perimenopause and menopause, this decline is expected, if not always welcome. But in younger people, persistent hormone dips aren’t “just part of getting older.” They can be a red flag pointing to medical conditions, lifestyle factors, or even certain treatments.

Ahead, we’ll break down what causes low estrogen, explain what’s normal with age, and flag when those signs of low estrogen—like hot flashes, vaginal dryness, or irregular cycles—might mean it’s time to talk to a provider.

What is estrogen?

Sure, you’ve heard the word tossed around in bio class, at your doctor’s office, maybe even on TikTok, but what is estrogen, really?

Think of estrogen as your body’s multitasking hormone. It’s best known for its role in puberty, periods, pregnancy, and menopause, but it also keeps the rest of your body healthy. Everyone (yes, people with penises, too!) makes estrogen, because it helps with:

• Balancing cholesterol and blood sugar
• Strengthening bones and muscles
• Supporting brain power and mood

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How estrogen changes across life stages

Puberty (10-13 yrs old on average)
Estrogen surges
Kick-starts periods, breast development, changes in body composition (hips widen, more body fat)

Reproductive years (20s-30s)
Levels rise and fall in a predictable cycle
Drives ovulation, fertility, and pregnancy prep (thins cervical mucus, giving sperm an easier swim toward the egg)

Postpartum
Estrogen levels fall to pre-pregnancy levels after birth
Stays low until ovulation returns (longer if breastfeeding)

Perimenopause (late 30s-40s)
Estrogen levels no longer follow the same predictable pattern of highs and lows experienced during the menstrual cycle of a person in their pre-perimenopause years
Estrogen spikes and dips unpredictably (may cause hot flashes, mood swings, irregular cycles, and other symptoms)

Menopause (40s-50s)
Estrogen bottoms out
Periods stop, symptoms like vaginal dryness, bone loss, and sleep issues can kick in

Types of estrogen

Your body makes three key types of estrogen, and each takes the spotlight at different stages of life:

• Estrone (E1): the only form the body keeps making after menopause.
• Estradiol (E2): the powerhouse hormone during your reproductive years (and the strongest form).
• Estriol (E3): peaks in pregnancy.

How much estrogen you produce also fluctuates throughout the life cycle. Here’s what that looks like in people with uteruses:

• Puberty: Estrogen levels surge, sparking breast development, wider hips, and more body fat. 
• Menstrual cycle: Estrogen teams up with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and progesterone to regulate your cycle. It triggers ovulation and thickens the uterine lining, prepping for possible pregnancy.
• Pregnancy and fertility: Right before ovulation, estrogen spikes, which is the signal your brain needs to increase LH and induce ovulation—making this your most fertile window. It also thins cervical mucus, giving sperm an easier swim toward the egg. 
• Menopause: Levels drop in perimenopause (the years leading up to menopause, typically in your early to mid 40s, but can sometimes occur in your late 30s), then bottom out around age 51, when, on average, periods stop for good in most people. This dip can trigger hot flashes, night sweats, mood shifts, and vaginal dryness.

While fluctuating estrogen levels during your cycle are totally normal in women, estrogen that stays too high or too low can point to a health issue (in people of all sexes). That’s why paying attention to your hormone health matters at every age.

What causes low estrogen as you get older?

Estrogen levels are higher in your teens and reproductive years, but things change as you age or after you have a baby. Here’s when and why your levels can nosedive:

Perimenopause and menopause

In your prime reproductive years, estrogen follows a pretty reliable rhythm—rising and falling in sync with your menstrual cycle. But as menopause approaches, that rhythm goes rogue. Levels can crash suddenly or surge higher than usual, but the overall direction is clear: a steady slide downward.

Here’s why this happens: As ovarian follicles dwindle with age, the granulosa cells (your main estradiol producers) shrink in number, too. This hormonal shift throws off the brain–ovary communication system (the hypothalamic-pituitary-ovarian axis), disrupting the delicate balance that keeps cycles regular. The result? Irregular periods that eventually stop altogether as menopause sets in.

Postpartum changes

If perimenopause is a slow fade, postpartum is a cliff dive. During pregnancy, estrogen—mostly made in the placenta—can skyrocket up to 1,000 times higher than usual to support fetal growth, build the uterus, and prep the body for breastfeeding. But once the placenta is delivered, levels plummet almost overnight to below pre-pregnancy levels. Estrogen stays suppressed until ovulation kicks back in weeks or months later.

If you choose to breast- or chest-feed, low estrogen levels can stick around for at least six months (or, for some, until you stop nursing). 

Possible causes of low estrogen by age

Teens–20s

• Medical: Turner syndrome, hypopituitarism, PCOS
• Lifestyle: Hypothalamic amenorrhea (undereating, over-exercising, eating disorders, poor nutrition), exposure to endocrine disruptors
• Treatment: Oophorectomy (removal of one or both ovaries), chemo, radiation, anti-estrogen therapies

20s–30s

• Natural: Postpartum + breastfeeding (estrogen suppressed until cycles return)
• Medical: PCOS, hypothyroidism, chronic kidney disease, premature ovarian failure
• Lifestyle: Chronic stress, exposure to endocrine disruptors
• Treatment: Oophorectomy, chemo, radiation, anti-estrogen therapies

40s–50s

• Natural: Perimenopause (hormone highs + lows)
• Medical: Hypothyroidism, chronic kidney disease, premature ovarian insufficiency
• Lifestyle: Chronic stress, poor nutrition, endocrine disruptors
• Treatment: Oophorectomy, chemo, radiation, anti-estrogen therapies

50s+

• Natural: Menopause (estrogen bottoms out)
• Medical: Hypothyroidism, chronic kidney disease
• Lifestyle: Stress, poor nutrition may worsen symptoms
• Treatment: Oophorectomy, chemo, radiation, and anti-estrogen therapies

What causes low estrogen when you’re younger?

Low estrogen isn’t just a midlife thing; it can crop up earlier, too. Here are some possible causes of low estrogen in your 30s and younger years.

Medical conditions, treatments, and surgeries

Sometimes, medical conditions are the hidden culprits throwing your hormones off balance. One common condition is polycystic ovary syndrome (PCOS): “PCOS is a condition where there is irregular ovulation and impaired development of follicles,” says Gouri Pimputkar, DO, FACOG, DipABLM, clinical lead at Allara Health. “When that happens, the normal conversion of androgens to estrogen at the follicular level is disrupted. This overall leads to an increased environment of androgens (hence the symptoms of increased hair growth and acne), and a reduced production of estradiol.” 

Other conditions that may lead to low estrogen in your 30s or below include: 

• Hypothyroidism: When the thyroid is sluggish and doesn’t make enough hormones, it can lead to irregular or infrequent periods, high prolactin levels, and—yep—lower estradiol. One study showed that thyroid hormone replacement therapy can bring estrogen back up to healthier levels.
• Hypopituitarism: When the pituitary gland doesn’t produce enough hormones. Without sufficient reproductive hormones like LH and FSH—the key players that tell the ovaries to do their thing—it can disrupt the body’s production of eggs and estrogen.
• Turner syndrome: A genetic condition where the ovaries don’t fully develop, often leading to very low estrogen. People with Turner syndrome may not go through typical puberty changes like breast development or getting a period.
• Primary ovarian insufficiency (aka premature menopause): Here, the ovaries run out of follicles needed to make eggs before age 40, which means they also stop producing enough estrogen. This was previously referred to as “premature ovarian failure (POF).” The condition leads to menstrual problems, infertility, and hallmark symptoms of low estrogen between puberty and age 40.
• Chronic kidney disease: When kidneys don’t function normally, waste buildup (uremia), other health conditions, and certain meds can potentially throw off the hypothalamic-pituitary axis. That disruption can contribute to irregular cycles, missed periods, or even early menopause.

Certain treatments or surgeries can also push you into menopause (and a steep estrogen drop) earlier than expected. These include:

• Bilateral oophorectomy (surgical removal of both ovaries)
• Chemotherapy (especially with alkylating agents)
• Pelvic radiation
• Therapies with anti-estrogen drugs

Lifestyle and environmental factors

Your daily habits (and even what’s in your environment) can mess with your estrogen more than you might think. Chronic stress is one factor. “In a roundabout way, yes stress (both physiological and psychological) can lead to alterations in the normal brain-to-ovary communication pathway, which ultimately will lead to decreases in estrogen levels,” says Dr. Pimputkar. Over time, stress dials down the signals that tell your ovaries to mature a follicle and ovulate, slashing production of both estrogen and progesterone, she explains. 

Another way lifestyle can contribute to low estrogen? When your hypothalamus goes into “survival mode,” your period can vanish (known as amenorrhea)—and with it, estrogen levels dip too. Triggers can include:

• Eating too little or restricting food
• Poor nutrition
• Intense exercise
• Emotional or psychological stress
• Very low body fat

Often, it’s not one of these factors but a combination that convinces your brain to shut down “non-essential” processes (like your period) in order to prioritize essentials like breathing and keeping your heart beating.

Another potential environmental case of low estrogen is endocrine-disrupting chemicals. Endocrine disruptors lurk in common items: cosmetics, plastics, food packaging, toys, even carpets. These everyday chemicals can throw off estrogen by disrupting the same brain-to-ovary pathway that stress affects, says Dr. Pimputkar. “Known offenders are Bisphenol A, phthalates, polychlorinated biphenyls, dioxins, and some pesticides,” she says. 

Research also suggests they can bind directly to estrogen receptors and alter gene expression in the ovary, which may reduce ovarian reserve or trigger premature ovarian insufficiency, Dr. Pimputkar adds.

What are symptoms of low estrogen?

When your estrogen dips, your body doesn’t exactly keep quiet about it. Some signals can be disruptive (hello, hot flashes) while others may be less obvious.

Common low estrogen symptoms include:

• Brain fog (trouble concentrating)
• Low sex drive
• Hot flashes
• Irregular periods
• Mood changes
• Sleep problems
• Vaginal dryness

In people with penises, estrogen deficiency symptoms may look like:

• Weight gain
• Dry skin
• Migraines
• Weakness, decreased muscle strength, and less stamina
• Brittle bones
• Reduced sex drive

Of course, these symptoms can overlap with other conditions, so don’t jump to conclusions. If you suspect low estrogen, talk to your provider. A simple blood test can confirm what’s really going on.

• Physical symptoms: brain fog, headaches, hot flashes, night sweats, fatigue, sleep problems, possible weight gain, increased risk of heart disease and osteoporosis  
• Emotional symptoms: mood changes, irritability, depression, or anxiety
• Sexual/reproductive health symptoms: low sex drive, irregular/missed periods, vaginal dryness, painful sex, infertility 

What complications are associated with low estrogen?

Low estrogen isn’t just about annoying hot flashes. It can ripple out to affect fertility, mood, metabolism, heart health, and even your bones. Here’s how:

Infertility

When you have a condition associated with low estrogen, you may have a more difficult time trying to conceive.

• Primary ovarian insufficiency: Ovaries stop working before age 40, leading to low estrogen and irregular ovulation. This often means infertility. It’s also sometimes known as premature ovarian failure (POF). Though the exact cause isn’t clear, primary ovarian insufficiency contributes to menstrual irregularities, ovarian atrophy, and is becoming a growing cause of infertility among people of childbearing age.

Mood and mental health

Estrogen impacts neurotransmitters like serotonin, dopamine, and GABA, all of which affect mood, behavior, and cognition. When estrogen levels fluctuate wildly—like during perimenopause—mood swings, anxiety, or even depression can follow. In fact, between one and two thirds of women report a decline in their mental health during perimenopause, and the risk of depression rises during the menopause transition. Not everyone who is a menopausal experiences depression, but shifting estradiol levels can make some more vulnerable to mood changes.

Metabolism

Yes, estrogen even plays a role in your jeans fitting (or not). “Decline in estrogen is linked to weight gain and changes in metabolism, especially in the context of perimenopause/menopause or premature ovarian insufficiency,” says Dr. Pimputkar. Here’s why, she explains:

• Loss of estrogen contributes to abdominal fat gain and abnormal cholesterol metabolism.
• Estrogen acts on the hypothalamus to help regulate appetite, metabolism, and fat distribution.
• Estrogen deficiency is tied to metabolic syndrome, insulin resistance, and a higher risk of cardiovascular disease.

Cardiovascular disease

Estrogen is a heart helper: It boosts HDL cholesterol and lowers LDL cholesterol. Once estrogen declines, that protection fades.

During menopause, women’s risk of coronary heart disease doubles or even triples compared to peers who haven’t reached menopause. That’s thanks to changes in cholesterol levels, blood vessel function, and other hormonal pathways that regulate blood pressure.

Osteoporosis

Estrogen is also a bone builder. During puberty, estrogen helps bones grow and fuse properly. When it drops, bone loss speeds up.

• Starting around age 40, women lose about 0.3% to 0.5% of bone per year.
• During menopause, bone loss accelerates to 3% to 5% per year for 5–7 years.
• This sharp decline raises the risk of osteoporosis, leaving bones thinner, weaker, and more fracture-prone.

How common is it? The data varies due to various factors, including race. Among U.S. Caucasian postmenopausal women, osteoporosis affects:

• 14% of women ages 50–59
• 22% of women ages 60–69
• 39% of women ages 70–79
• 70% of women ages 80+

African American and Hispanic women may have a lower overall risk of osteoporosis compared to white and Asian women, but that doesn’t mean they’re in the clear. Black women, for instance, typically have higher bone density and a lower incidence of osteoporosis, but health disparities and other risk factors still leave them vulnerable to the disease and severe complications, including worse health outcomes after experiencing hip fractures.

How is low estrogen diagnosed?

If you suspect low estrogen, get tested. The most common approach is a blood test, but sometimes your provider may order a urine test. In the case of a 24-hour urine collection, you’ll get a special container and instructions to save every drop of pee for a full day so the lab can measure hormone levels more precisely.

For women, tests often measure estradiol and/or estrone to help uncover what’s behind symptoms. Low (or high) estrogen can point to a range of conditions, including:

• Early or late puberty
• Polycystic ovary syndrome (PCOS)
• Thyroid or pituitary disorders (like hypothyroidism)
• Infertility
• Certain ovarian tumors
• Perimenopause

Because women’s estrogen levels naturally rise and fall with cycles, you may need repeat testing to see trends over time rather than relying on one single number.

For those assigned male, estrogen testing helps explain issues like:

• Delayed puberty
• Breast growth (gynecomastia)
• Infertility
• Erectile dysfunction (ED)
• Testicular or adrenal tumors

Estrogen levels in the male sex don’t swing much day to day, so if levels come back unusually high or low, it’s often a clear red flag for an underlying condition.

What are the most effective ways to increase estrogen levels?

You can give your estrogen a helping hand. There are no magic fixes here, but smart lifestyle tweaks (and medical treatments when needed) can make a big difference.

Lifestyle and natural approaches

If you’re dealing with low-estrogen symptoms, there are ways to naturally support your body’s hormone production. Think of it as giving your estrogen a little TLC through everyday choices.

Vitamins and minerals

Certain nutrients play a direct role in estrogen production and balance. These include:

• Boron: helps your body absorb estrogen and testosterone.
• Vitamin B: essential for making and metabolizing estrogen.
• Vitamin D: technically a hormone, it also supports estrogen production.
• Vitamin E: may ease hot flashes, insomnia, and other symptoms linked to low estrogen.

Other supplements

Some herbal and hormonal supplements may ease symptoms related to low estrogen, but remember—these aren’t FDA-regulated. Always talk to your provider before trying them. Popular options include:

• Black cohosh: used for menopause symptoms, with some evidence it reduces hot flashes
• DHEA: a synthetic version of a natural hormone that can convert into estrogen (and testosterone)
• Red clover: Early research shows it may help with hot flashes, but whether it boosts estrogen is still unclear.

Sleep

Quality sleep is like your hormone reset button. It keeps your hormones—including estrogen—in balance.

Stress management 

Chronic stress triggers your body to pump out cortisol and adrenaline, which can throw off your estrogen levels. Translation: Stress management isn’t just about your mental health; it’s good for your hormone health, too.

Exercise 

Regular exercise supports hormone balance, better sleep, and healthy body composition. But too much of a good thing (hello, overtraining) can backfire on your estrogen levels.

Balanced diet

Cutting back on added sugars and loading up on fiber and healthy fats (like olive oil, nuts, seeds, and fish) can promote hormone balance and overall well-being.

Medical approaches

When symptoms of low estrogen really start messing with your quality of life, medical treatments may be the next step. The most common option is hormone replacement therapy (HRT), but non-hormonal options such as cognitive behavioral therapy, medication, and lifestyle changes can also treat symptoms caused by low estrogen. 

HRT involves small doses of estrogen (for those with a uterus, this is usually paired with progesterone), says Dr. Pimputkar. For people with low estrogen due to perimenopause, menopause, or premature ovarian insufficiency, HRT can offer relief from hot flashes, night sweats, and vaginal dryness—plus protection against bone loss, Dr. Pimputkar explains.

Of all the estrogen forms, estradiol is the gold standard for HRT. The FDA has approved it for managing menopause symptoms, and research shows it can improve quality of life while reducing the risk of osteoporosis and even coronary artery disease when treatment is begun at the onset of menopause.

There’s no one-size-fits-all with HRT; your provider will tailor the approach to your symptoms, age, and health history. Delivery options include:

• Oral tablets
• Vaginal ring (inserted and replaced every few months)
• Injections (delivered directly into a muscle)
• Transdermal (patches, sprays, creams, or vaginal tablets/inserts)

While HRT can be life changing for some, it isn’t for everyone. For example, systemic hormone therapy in women over 60 can increase the risk of coronary artery disease, blood clots, or stroke. That said, low-dose local options (like vaginal creams or tablets) carry much less risk.

“The key for hormone therapy is that it is an individualized approach,” says Dr. Pimputkar. “Each patient needs to be evaluated individually to see if they are a good candidate…and to see if the benefits outweigh the risks.” 

When should I see a doctor?

Low estrogen is a normal part of aging, but suffering through symptoms isn’t. If symptoms like hot flashes, sleep troubles, or mood swings are hijacking your quality of life, it’s time to check in with a pro. And if you’re under 40 or your symptoms feel severe, that’s an even stronger signal something deeper may be going on.

Common red flags that deserve a doctor’s attention include:

• Hot flashes and night sweats
• Irregular or missed periods
• Recurring headaches or brain fog
• Extreme fatigue or poor sleep
• Mood changes, irritability, or depression
• Vaginal dryness or painful sex

Getting diagnosed early doesn’t just bring short-term relief; it also helps lower your risk for bigger issues later, like osteoporosis and heart disease. Clinical experts like those at Allara can evaluate, treat, and support you from diagnosis through treatment.

The bottom line

Estrogen touches everything from your cycles to your mood to your long-term health. While dips are normal with age, persistent symptoms like hot flashes, brain fog, or painful sex aren’t something you need to just “deal with.” Ignoring low estrogen can raise your risk for serious issues like heart disease and osteoporosis down the line.

The good news? Relief is possible. A qualified clinician can investigate, diagnose, and create a personalized treatment plan so you can finally get to the bottom of your symptoms and feel like you again.

Key takeaways

• Estrogen isn’t just about reproduction. It also supports your brain, bones, heart, and metabolism.
• Low estrogen can happen with age, after pregnancy, from medical conditions, or even lifestyle factors like stress and under-eating.
• Symptoms range from hot flashes and brain fog to vaginal dryness, irregular periods, and mood changes.
• Untreated low estrogen can lead to bigger health issues, including infertility, osteoporosis, and heart disease.
• Both lifestyle shifts (stress management, diet, supplements) and medical treatments (like HRT) can help restore balance—what’s best depends on you.

Frequently asked questions (FAQs)

What happens to the body if estrogen is low?

When estrogen levels are low, you might experience symptoms like:

•  Brain fog (trouble concentrating)
• Low sex drive
• Hot flashes
• Irregular periods
• Mood changes
• Sleep problems
• Vaginal dryness

Over time, an estrogen deficiency can even increase your risk for chronic health problems like cardiovascular disease and osteoporosis.

What causes low estrogen in your 20s?

While estrogen levels normally dip in midlife due to menopause, low estrogen can happen in your younger years for a variety of reasons:

• After pregnancy
• Medical conditions (including PCOS, hypothyroidism, hypopituitarism, Turner syndrome, primary ovarian insufficiency, chronic kidney disease, and hypothalamic amenorrhea)
• Chronic stress
• Exposure to endocrine-disrupting chemicals
• Medical treatments and surgeries (that force you into early menopause including bilateral oophorectomy, chemotherapy, pelvic radiation, and therapies with anti-estrogen drugs)

Does low estrogen cause weight gain?

If the number on the scale has been creeping up, low estrogen might be part of the puzzle. As estrogen declines—especially during perimenopause, menopause, or premature ovarian insufficiency—your metabolism can shift, says Dr. Pimputkar. Here’s how, she explains:

• Less estrogen often means more belly fat and changes in cholesterol, according to Dr. Pimputkar.
• Estrogen normally works with the hypothalamus to help regulate appetite, energy, and fat distribution.
• Without it, the risk of metabolic syndrome, insulin resistance, and cardiovascular disease climbs.

Can stress cause low estrogen?

Short answer: yes. Chronic stress—whether physical or emotional—can throw off the delicate brain-to-ovary communication system, says Dr. Pimputkar. When your hypothalamic-pituitary-ovarian axis is disrupted, your ovaries don’t get the signal to release mature follicles, ultimately resulting in lower estrogen (and progesterone), she explains.

Over time, that hormonal dip can show up as irregular (or missing) periods, bone loss, and a body that feels out of balance. So while stress might feel “all in your head,” it may be tied to what’s happening in your ovaries too.

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